Thrusting device

ABSTRACT

A thrusting device comprising a plurality of fixed rail plates for shifting an article to be shifted thereon, each of said fixed rail plates being formed therein with substantially equally spaced pin holes arranged substantially along the center line thereof, and at least one thrusting unit striding over a selected one of said fixed rail plates and comprising running wheels provided at the bottom thereof for running along said fixed rail plate, one front block and one rear block arranged in opposed relation to each other, one thrusting hydraulic cylinder having one end connected to said front block and the other end to said rear block for thrusting said front block with said other end bearing against said rear block, supporting means for securing both of said blocks alternately to said fixed rail plate through said pin holes, two guide beams each having one end fixed to said front block and the central portion slidably supported by a bearing portion formed integrally with said rear block, and antistumbling means connected to said rear block rearwardly of said supporting means.

United States Patent 1191 Muto 'et a1. 9

1 11 3,832,945 1451 Sept.3,1974

Primary Exami ne'w-Drayton E. Hoffman 1 THRUSTING DEVICE Y [75]Inventors: Masataro Muto, Tokyo; Shingo g i Agent Darby Nishioka,Nagasaki; Toshihiro Naka, us man Nagasaki; Akio Kanesaki, Nagasaki;:(anae Tokumura, Yokohama, all Of 57 ABSTRACT apan A thrusting devicecomprising a plurality of fixed rail [73] Asslgnee: 'E Julmgyo Kabushlk'plates for shifting an article to be shifted thereon, each Tokyo Japanof said fixed rail plates being formed therein with sub- [22] Filed:Jan. 24, 1973 stantially equally spaced pin holes arranged substantiallyalong the center line thereof, and at least one [21] Appl' 326479thrusting unit striding over a selected one of said fixed rail platesand comprising running wheels provided at [52] us. 01 104/154, 104/162,254/107 the bottom thereof for running along said fixed rail 511 1m. 011361b 13/12, B66f 1/00 p one from block and n rear block arranged in[58] Field of Search 104/147, 154, 162; pp relation to each other,thrusting y 105/29 R, 30, 31, 32, 161; 173/24, 46, 141, lic cylinderhaving one end connected to said front 156, 160; 175/92, 122; 299/31,70; 254/105 block and the other end to said rear block for thrust- 106107 ing said front block with said other end bearing against said rearblock, supporting means for securing [56] R f e Ci d both of said blocksalternately to said fixed rail plate UNITED STATES PATENTS through saidpin holes, two guide beams each having 2 822 670 8 d 7 one end fixed tosaid front block and the central por- Z132 2:8: tion slidably supportedby a bearing portion formed 29928l2 7/1961 'ggg'i 254/107 integrallywith said rear block, and anti-stumbling 3:008:69! 11/1961 Steele et al.11:: 254/106 means connected to d rear block rearwardly of Said3,290,007 12/1966 Yeilding 254/106 supportmg means- 3,722,863 3 1973 1:h 254 105 l o 3 Claims, 6 Drawing Figures E I] If I i 5 I] a 2 5 44 s//I 2 W7 SHEH 1 OF 4 PATENTED 31974 THRUSTING DEVICE BACKGROUND OF THEINVENTION:

1. Field of the Invention This invention relates to a thrusting devicefor shifting largesized structures such, for example, as a structureunit of ship hull a predetermined distance stroke by strokeintermittently along a horizontal or substantially horizontal fixed bed.

2. Description of the Prior Art:

In conventional ship building methods, namely in building a ship on aninclined building berth set on the ground, it has been usual to assemblehull blocks one after another on blocks and place the weight of the hullon a launching way for the first time at the point when the entire hullstructure has been completed, for launching it therefrom, and inbuilding a ship on a building berth set within a dry clock, it has beencustomar y to construct and assembly the blocks of the ship hulldirectly on the fixed building berth and launch the completed ship hullby pouring water into the dry dock.

In recent years, there is the tendency that ships to be built arebecoming larger and larger in size, and such tendency is in increasingtrend. Under such circumstances, the conventional ship building methodsdescribed above are being subjected to many changes because, in theconventional methods using an on-theground building berth or a dry dock,an elongated building berth must be used over an extended period, sothat the working efficiency of the berth is poor and further, at somelocations, ship building by use of the building berth is impossible oruneconomical if not, due to the conditions of the locations. I

For instance, a new ship building method is consid- I ered and about tobe put in practical use, which comprises dividing a ship .hulllongitudinally into a plurality of blocks in the design stage, buildingthe respective blocks at specific locations, and shifting the completedblocks in one direction to join them together one after another, or inother words, a method in which each of the completed blocks is shifted apredetermined distance stroke by stroke on a fixed bed such as abuilding berth and thereby all of the completed blocks are joinedtogether to form a ship hull.

However, such a ship building methodcalls for a device by which eachhull block of a large size and heavy weight is shifted a predetermineddistance intermittently, safely and positively.

SUMMARY OF THE INVENTION I and can be produced at a low cost.

The characteristic feature of the thrusting device according to thepresent invention lies in that a front block and a rear block connectedwith each other by a hydraulic cylinder in such a manner that they aremovable alternately relative to each other like an inch worm are set ona fixed rail plate on which an article it is possible to shift thearticle stroke by stroke on said fixed rail plate, so that the thrustingdevice of the invention is well adapted for use in the rational shipbuilding by the hull block thrusting method.

The device of the invention is particularly advantageous in that, sincehydraulic cylinder is used as drive source for each constitutionalmember, the operation is very easy and in addition, the stroke ofmovement of the front block or rear block can be limited simply byfixing the other one of them to the rail plate or, more specifically, byproviding the pin holes in the rail plate and providing a pin member oneach of said blocks, which are engageable and disengageable in and fromsaid pin holes, so that the production is simple and the operation iseasy and further the stroke of each block can be limited positively,there being no chance of erroneous operation.

It is also to be noted that, since in the present invention, the frontblock and rear block are movable along the fixed rail plate on which thearticle is to be shifted and further, they are operated by one hydrauliccylinder, the entire device can be provided in a relatively small size.This is advantageous in that the device can be placed beneath the hullin the event when the entire device is used for thrusting a hull block,ensuring a positive and safe thrusting operation without inteferringwith other operation.

Further, in the device of the invention, pusher blocks are provided atthe forward end of the front block, which are connected to said frontblock through universal joints at all four sides of the forward end faceof said block, and can be fixed in their positions or movable relativeto said block as desired. Therefore, the thrust of the thrusting devicecan be effectively transmitted to the article to be shifted, through thepusher blocks which are applied to said article with a uniform pressure,and thus, local concentration of the thrust can be avoided and hencebreakage of the. constituent members of the device can also be avoided.

Further, in the device of the invention, a braking coupling member isprovided on the front block, which is engageable'with the article to beshifted and said article, during shifting, is always coupled with thefront block through said braking coupling member. Therefore, runaway ofthe article can be prevented without using any complicated braking meanswhich has been required heretofore. The present invention will bedescribed by way of example in greater detail hereunder with referenceto the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showingbreifly the state in which a ship hull block is being shifted by anembodi-. ment of the thrusting device according to the invention;

FIG. 2 is a top plan view showing the details of one thrusting unit ofthe thrusting device;

FIG. 3 is a front elevational view of the thrusting unit;

DESCRIPTION OF THE PREFERRED EMBODIMENT First of all, the constructionof the thrusting device of the invention will be described withreference to FIGS. 1 through 6.

In the drawings, reference numeral 1 designates a foundation and 2designates a plurality of equally spaced parallel fixed rail platesfixedly mounted on the foundation 1 each through the intermediary of acushion rubber plate 3. On each of the fixed rail plates 2 are providedrollable steel balls 4, 4 which are arranged in a plurality of rowsspaced from each other by a predetermined interval and retained byretainers 5, 5 respectively.

A slide bed 6 is mounted on the steel balls 4, 4 which has a rail plate8 attached to the underside thereof through a cushion rubber plate 7'and a block 9 provided at the upper side thereof for supporting a hullblock A. This slide bed 6 slides on the fixed rail plate 2, with thehull block A mounted thereon. A plurality of the slide blocks 6, 6 maybe coupled together by couplings according to the size of the hull blockA.

Specific ones of the fixed rail plates 2, 2....., i.e., two fixed railplates 2, 2 at such locations where the slide bed 6, 6 resting thereonwill maintain the hull block A in a balanced position during shifting ofsaid hull block, are each'formed with substantially equally spaced pinholes l1, l1 along the longitudinal center line thereof. The foundation1 is also formed with holes therein in a suitable depth at locationscorresponding to the locations of said pin holes 11, ll e A thrustingunit 12 is provided striding over the fixed rail plates 2, 2 having thepin holes 11, 11 for movement in the longitudinal direction of said railplates. The detailed construction of the thrusting unit 12 is shown inFIGS. 2 through 6. Namely, the major components of the thrusting unit 12are arranged symmetrically with respect to the longitudinal center linebetween the fixed rail plates 2, 2.

Now, the construction of the thrusting unit 12 will be describedpractically with reference to FIGS. 2 through 6. The thrusting unit 12includes a front block 13 striding over. the fixed rail plates 2, 2 andbeing movable along said fixed rail plates. Thisfront block 13 has aforked coupling portion 14 at a location corresponding to the centerline between the two fixed rail plates 2, 2, a vertically extending pinhole 15 and bearing portions16, 16 at two locations of the intermediateportion thereof.

The thrusting device of the invention also include a rear block 17 whichforms a pair with the front block 13 and similarly strides over thefixed rail plates 2, 2 for movement along said fixed rail plates. Thisrear block 17 is formed with a forked coupling portion 18 at a locationcorresponding to the coupling portion 14 of the front block, avertically extending pin hole 19 and arms 20, 20 projecting forwardlyfrom the intermediate portion of the front face thereof. The arms 20, 20are respectively provided with hearing portions 21, 21 and 22, 22,corresponding to the bearing portions 16, 16 of the front block 13connected to said arms 20, 20.

A hydraulic cylinder 23 is disposed between the front block 13 and rearblock 17, with the opposite ends thereof rotatably connected to thecoupling portion 14 of said front block and the coupling portion 18 ofsaid rear block through coupling pins 24, 24 respectively,

and in the embodiment illustrated in FIG. 6 the positions of connectionof both ends of said hydraulic cylinder are at the same level.

In another embodiment (not shown), the position of connection betweensaid hydraulic cylinder and rear block is lower than that of connectionbetween said hydraulic cylinder and front block so that the inner stressin the guide members 35, 35 may be reduced.

A front pin cylinder 25 is disposed in the pin hole 15 of the frontblock 13, and a front pin 26 is slidably disposed in said pin hole 15below the pin cylinder 25, with the upper end thereof connected to saidfront pin cylinder so that the lower end thereof may be engaged in eachof the pin holes 11, ll formed in the fixed rail plate 2. The rear block17 is provided with a rear pin cylinder 27, and a rear pin 28 isslidably disposed in the pin hole 19 of said rear block. The rear pin 28is connected at its upper end to the rear pin cylinder 27 through alinkage, so that the lower end thereof may be engaged in each of the pinholes 11, ll formed in the fixed rail plate 2.

Auxiliary frame beds 29, 29 are provided extending between the oppositeends of the front block 13 and rear block 17, with the front endsthereof connected to the oppositeends of said front block 13, andbearing portions 30, 30 corresponding to the bearing portions 16, 16 ofthe. front block 13 are provided at fixed positions of the rear ends ofsaid auxiliary frame beds integrally therewith.

Wheels 31, 31 are rotatably supported on the underside of the front andrear end portions of the auxiliary frame beds 29, 29 through bearings32, 32 respectively. A high torque motor 33 is provided for each frontwheel 31 to drive the same through a transmission mechanism 34 includinga sprocket and a chain.

Guide beams 35, 35 are respectively slidably supported at their centralportions by the bearing portions 21, 21 and 22, 22 of the rear block 17,with the opposite ends thereof journaled in the bearing portions 16, 16of the front block 13 and the bearing portions 30, 30 of the auxiliaryframe beds 29, 29, and held in positions by means of fixed nuts 36, 36

On the auxiliary frame beds 29, 29 are respectively mounted mainhydraulic pumps 37, 37 and auxiliary hydraulic pumps 38, 38 which arerespectively connected directly withthe hydraulic cylinder 23, the frontpin cylinder 25 and the rear pin cylinder-27 to operate the same. Alsomounted on the auxiliary frame beds 29, 29 are drive motors 39, 39 whichare respectively connected directly with the main hydraulic pumps 37, 37and auxiliary hydraulic pumps 38, 38. Reference numerals 40, 40designate oil tanks provided on the auxiliary frame beds 29, 29respectively.

Hydraulic valve means 41, 41 are provided on the auxiliary frame beds29, 29 respectively for controlling flow of oil between the oil tanks40, 40 and the respective cylinders through the main hydraulic pumps 37,37 and auxiliary hydraulic pumps 38, 38.

Provided on the front face of the front block 13 is a pusher block 42which is connected to said front block so as to be pivotable in ahorizontal plane and provided at its front lower end with an engagingportion 43 for engagement with the lower portion of, the confronting endof the slide bed 6. The front face of the pusher block 42 is in contactwith the confronting end face of the slide base 6 through theintermediary of a cushion rubber 44.

Coupling arms 45, 45 are pivotally connected at their rear ends to theopposite sides of the pusher block 42 by means of pins 47, 47, and thefront ends of said coupling arms 45, 45 are respectively formed withholes 46, 46 for engagement with connecting rods 48 projecting from theslide bed 6. Each of the arms 45, 45 is provided with a stopper pin 49which is connected to the central portion of said arm by way of a chain.This stopper pin 49, when the arm 45 is engaged with the connecting rods48, 48 is inserted into holes formed in the projecting ends of said rods48, 48.

The rear block 17 is provided at the center of its rear end withanti-stumble menas 50. The rear block 17 is also provided with a fixingmain hydraulic cylinder 51 which has one end supported by a bracket 52provided on said rear block, a fixing block 53 supported through aneccentric pin 55 by a bracket 54 also provided on said rear block and anauxiliary fixing hydraulic cylinder 56 having one end supported by thepiston of said main hydraulic cylinder 51 and the other end connectedfixedly to said eccentric pin 55.

An operation control compartment 57 having an actuation board and acontrol board therein is provided at one side of one of the auxiliaryframe beds 29, and electric means 58 comprising a power cable windingand unwinding reel is also provided at one side of the one of theauxiliary frame beds 29, as shown in FIG. 2.

In the construction of the embodiment of the invention described indetail hereinbefore, the hydraulic cylinder 23, the front pin cylinder25, the rear pin cylinder 27, the main hydraulic pumps 37, 37, theauxiliary hydraulic pumps 38, 38, and further, the fixing main hydrauliccylinder 51, the fixing auxiliary hydraulic cylinder 56 and the oiltanks 40, 40 are respectively connected with each other through thehydraulic valve means 41, 41 by suitable conduits though not apparent inthe drawings, so that operating oil may be supplied thereto ordischarged therefrom. Further, the drive motors 39, 39 are electricallyconnected with the electric means 58 by a suitable electrical wiring notshown. All of these elements are controllably operated from theoperation control compartment 57.

Now, the operation of the thrusting device of the invention will beexplained hereunder: As stated, the slide beds 6, 6 having the hullblock A mounted thereon are placed on the fixed rail plates 2, 2 withthe steel balls 4, 4 interposed therebetween.

When the hull block A has been completed and the time has come when thecompleted hull block is to be shifted forward, the thrusting units 12,12 are placed on those of the fixed rail plates 2, 2 on which saidthrusting units are to be operated.

Namely, the high torque motors 33, 33 of each thrusting unit 12 are setin motion under such condition that the front block 13 and the rearblock 17 of said thrusting unit are in their closest positions to eachother, to drive the wheels 31, 31 of said thrusting unit and to placethe thrusting unit in a position to stride over the fixed rail plate 2,at the rearportion of said rail plate.

Thereafter, each thrusting unit 12 is advanced slowly along the fixedrail plate 2 until it abuts against the rearmost one of the slide beds6, 6 carrying the completed hull block thereon. Then, the engagingportion 43 of the pusher block 42 of each thrusting unit 12 is engagedwith the associated slide bed 6 and the cushion rubber 44 at the frontface of said pusher block is contacted with said slide bed 6.

The arms 45, 45 at the opposite ends of the pusher block 42 arepivotally turned and engaged with the connecting rod 48, 48 provided onthe slide bed 6 and the stopper pins 49, 49 are inserted into the holesat the projecting ends of said connecting rods, whereby the pusher block42 is coupled'with the slide bed 6.

After all of the thrusting units 12, 12 have been coupled with theassociated slide beds 6, 6 respectively in the manner described, thehydraulic valve means 41, 41 of each thrusting unit 12 are adjusted andthe drive motors 39, 39 thereof are set in motion, to supply pressurizedoil through the auxiliary hydraulic pumps 38, 38 to the rear pincylinder 27, the fixing main hydraulic cylinder 51 and fixing auxiliaryhydraulic cylinder Si of the rear block 17, to actuate the same, wherebythe rear pin 28 is engaged in the pin hole 11 of the fixed rail plate 2and concurrently, the fixing block 53 is de- In the constructiondescribed above, the-interval of the pin holes 11, ll formed in thefixed rail plates 2, 2 is determined by the desired stroke of movementof the hull block A at each intermittent movement of said hull block.Thisstroke hasa direct relation with the stroke of the thrustinghydraulic cylinder 23 of each thrusting unit 12. In the embodimentshown, the stroke pressed against the fixed rail plate 2 to secure therear block 17. In this case, the front pin 26 of the front block 13 ofeach thrusting unit 12 is held retracted into the pin hole 15.

Upon completion of the above operation, the hydraulic valve means 41, 41are operated and the drive motors 39, 39' of each thrusting unit 12 areset in motion, whereupon thethrusting hydraulic cylinders 23 of allthrusting units 12, 12 are actuated all at once through the respectivemain hydraulic pumps 37 37 and thereby the front blocks 13 of saidthrusting units 12, 12 are moved forward relativeto the fixed rearblocks 17, with the pusher blocks 42 at the front ends thereof pushingthe respective slide beds 6, 6 Theslide beds 6, 6 thus pushed slide onthe steel balls 4, 4 carrying thehull block A mounted thereon forwardlyalong the fixed rail plates 2,2

Since the stroke of the thrusting hydraulic cylinders 23 is set at 1meter, the slide beds6, 6 are shifted 1 meter by the above-describedoperation and accordingly the hull block A is shifted also v1 meter.

Upon completion one stroke of the shifting operation by the thrustinghydraulic cylinders 23 of the respective thrusting units 12, 12described above,-said thrusting hydraulic cylinders 23 stop theiroperation, so that the front blocks 13 stop their forward movement andthe pusher blocks 42 thereof also stop. The slide beds 6, 6 are heldstationary by the arms 45, 45 coupling said slide beds 6, 6 whith thepusher blocks 42, and concurrently, the shifting of the hull block A isended.

Now, the position of the hydraulic valve means 41, 41 of each thrustingunit 12 is shifted and pressurized oil is supplied to the front pincylinder 25 of the front block 13, to operate the same, whereby thefront pin 26 is inserted into the pin hole 11 of the fixed rail plate 2.On the other hand, the rear pin cylinder 26 of the rear block 17 isactuated to move the rear pin 28 off the pin hole 11. At the same time,the fixing main hydraulic cylinder 51 and fixing auxiliary hydrauliccylinder 56 of the anti-stumble means 50 are actuated to disengage thefixing block 58 from the fixed rail plate 2 and thereby to provide formovement of the rear block 17 along the fixed rail plate 2.

Successively thereafter, the drivemotors 39, 39 of each thrusting unit12 are operated under the condition described above and pressurized oilis supplied through the main hydraulic pumps 37, 37 to thrustinghydraulic cylinder 23 in a direction reverse to the case of thrustingoperation, whereby said thrusting hydraulic cylinder 23 operates to movethe rear block 17 toward the front block 13. In this case, the stroke ofmovement of the rear block is 1 meter, same as the stroke of forwardmovement of the front block 13.

When the rear blocks 17 of all of the thrusting units 12, 12 have moved1 meter toward the front blocks 13, the operation of the thrustinghydraulic cylinders 23 is terminated, so that the rear blocks 17 stoptheir movement.

Thereafter, the rear pin cylinder 27 provided on the rear block 17 ofeach thrusting unit 12 is actuated again to insert the rear pin 28 intothe next pin hole 11 of the fixed rail plate 2 to fix said rear block 17in its position. At the same time, the front pin cylinder 25 provided inthe front block 13 is actuated to pull the front pin 26 off the pin hole11 of said fixed rail plate 2, providing for movement of the frontblock. Then, all of the slide beds 6 are thrusted all at once by thefront blocks .13 through the pusher blocks 42in the same manner asdescribed previously, upon actuating the thrusting hydraulic cylinders23 of the respective thrusting units, whereby the hull block A isadvanced another 1 meter.

When the hull block A has been shifted 1 meter, the

rear block 17 of each thrusting unit 12 is set free from the fixed railplate 2 by the same operation as described above, and now the frontblock is secured to said rail plate, and the rear block is pulled towardsaid front block.

With the thrusting device of the invention, the hull block A is shifted1 meter by one meter intermittently along the fixed rail plates 2, 2 byrepeating sequentially the steps of selecting the position of thehydraulic valve means 41, 41 of each thrusting unit 12; driving thedrive motors 29, 29; to supply pressurized oil from the oil tanks 40, 40through the auxiliary hydraulic pumps 38, 38 alternately to the frontpin cylinder 25 and to the rear pin cylinder 27, the fixing mainhydraulic cylinder 51 and the fixing auxiliary hydraulic cylinder 56,thereby to engage the front pin 26 and rear pin 28 alternately in thepin holes 11, 11 of the fixed rail plate 2; and secure the front block13 and rear block 17 alternately to said fixed rail plate, said rearblock 17 being secured to said fixed rail plate by the fixing block 58which is depressed against the rail plate surface while said rear pin 28is being engaged in said pin hole 11; and driving the drive motors 39,39 while said rear block 17 is being secured to said rail plate 2 tosupply pressurized oil from the oil tanks 40, 40 through the mainhydraulic pumps 37, 37 to the thrusting hydraulic cylinder 23 thereby toactuate said thrusting hydraulic cylinder 23 and thrust the slide bed 6forward by said front block 13 through the pusher block 42.

In the thrusting operation of the device of this invention, theauxiliary frame beds 29 of each thrusting unit 12 and various elementsmounted on said auxiliary frame beds, the guide beams 35, 35, theoperation control compartment 57 and the electric means 58 move alongwith the front block 13.

Further, in the thrusting operation, the front block 13 and rear block17 of each thrusting unit 12 move always straight along and in adirection parallel to the associated fixed rail plate 2 when said frontblock is pushed forward or said rear block is pulled toward said frontblock, because both of said blocks 13, 17 are coupled together by thethrusting hydraulic cylinder 23 interposed therebetween and the twoguide beams 35, 35 in sliding engagement with said blocks.

After the hull block A has been moved 1 meter by 1 meter over a desireddistance on the fixed rail plates 2, 2 by repeating the above-describedoperation, the drive motors 39, 39 of each thrusting unit 12 are set inthe front pin 26 of the front block 13 and the rear pin 28 of the rearblock 17 off the pin holes 11, 11 of said I fixed rail plates 2, 2 andput said front and rear block together.

Then, the pusher block 42 of each thrusting unit 12 is disengaged fromthe associated slide bed 6 by disconnecting the arms 45, 45 from saidslide bed.

Thereafter, the high torquemotors 33, 33 of each thrusting unit 12 areset in motion to drive the wheels 31, 31 of said thrusting unit andreturn said thrusting unit to the original starting point.

With all of the thrusting units 12, 12 having thus been returned totheir original positions, another hull block A is constructed on theslide beds 6, 6 and the completed hull block A is transported apredetermined distance along the fixed rail plates 2, 2 by the thrustingunits 12, 12 respectively connected with the rearmost ones of the slidebeds 6, 6 and operated in the same manner as descirbed above.

. According to the construction of the thrusting device of theinvention, there can be materialized a novel thrusting unit 12 whichissimple in construction, easy to manufacture, andsmall in size andhence requires a small space and which can be movable by making use ofthe fixed rail plate 2, and it becomes possible to transport a heavyhull block A more safely and simply than heretofore.

Namely, the thrusting units 12, 12 of the thrusting device according tothe invention each comprises one front block 13 and one rear block 17respectively striding over a fixed rail plate 2, one thrusting hydrauliccylinder 23 coupling said front and rear blocks with each other, onefront pin 26 provided in said frontblock 13 and one rear pin 28 providedin said rear block 17, one front pin cylinder 25 provided on said frontblock 13 to operatesaid front pin 26 and one rear pin cylinder 27provided on said rear block 17 tooperate said rear pin 28, a fixingblock 53 provided on said rear block 17 and a hydraulic cylinderprovided on said rear block 17 to operate said fixing block 53, and eachof these constituent members is of a relatively simple shape andconstruction and very easy to manufacture and assemble, and can beoperated simply and easily.

In the operation of each thrusting unit 12 according to the invention,the front block 13 and the rear block 17 are moved forward alternatelyby the action of the thrusting hydraulic cylinder 23 while altematelybeing secured to the fixedrail plate 2 by the front pin 26 and by therear pin 28 and fixing block 53, so that a large thrust can be obtainedsimply effectively and shifting of the heavy weight hull block A can beachieved easily.

Particularly when the front block 13 is moved forward by the action ofthe thrusting hydraulic cylinder 23, with the rear block 17 being fixedto the fixed rail plate 2, the reaction of the thrust of said hydrauliccylinder is taken by said fixed rail plate 2 through the rear pin 28 andfixing block 53. Owing to such arrangement, a rotational movement of therear block 17 can be prevented highly effectively and at the same time,the cost of manufacture of the thrusting unit can be substan tiallyreduced as the fixed rail plate 2 is effectively utilized.

It should also be noted that the wheels 31, 31 during the hull blockthrusting operation are not subjected to an unreasonably large forcesince the reaction of thrust is taken by the fixing block 53, and thusbreakage of said wheels can be avoided.

In the thrusting operation, the pusher block 42 of each thrusting unit12, which is connected to the front block 13 in a manner to be pivotablein a horizontal plane, is applied to the rear end face of the slide bed6. Therefore, it is possible to transmit the thrust of the thrustinghydraulic cylinder 23 uniformly to the slide bed 6. The slide bed 6 andthe pusher block 42 of the front block 13 are firmly engaged with eachother at the lower portions thereof and, therefore, there is no fear ofsaid slide bed and pusher block slipping relative to each other duringthe thrusting operation. Since the hull block A having-a large weight ismounted on the slide bed 6 and the rear block 17 of each thrusting unit12 is firmly engaged with the fixed rail plate 2 and further thethrusting hydraulic cylinder 23 is arranged such that its thrust actsforwardly, none of the constituent members of the thrusting unitundergoes an unreasonably large force during the thrusting operation andhence breakage or rotational movement of said thrusting unit can bepositively prevented.

The construction of the thrusting units 12, 12 proper is so simple asmay be seen from the drawings that the entire thrusting units can bedisposed beneath the hull block A for carrying out the thrustingoperation, and the other operations are not adversely affected by thethrusting units. This is advantageous also in avoiding the breakage ofthe thrusting units which would otherwise be caused by articles droppingonto said thrusting units.

The front block 13 and rear block 17 are interconnected by the two guidebeams 35, 35, fixed to said front block 13, in such a manner that saidblocks may be movable independently of each other. Therefore, the frontand rear blocks are always restrained by each other from movement orrotation in a direction other than the thrusting direction. This ensuresaccurate and positive movement of both blocks by the thrusting hydrauliccylinder 23 and enables the thrust of said thrusting hydraulic cylinderto be transmitted in the correct direction to the slide bed 6 and thehull block A to be effectively thrusted.

In the thrusting operation, each of the slide beds 6 carrying the hullblock A thereon is coupled with the pusher block 42 of each thrustingunit 12 by means of the coupling arms 45, 45, so that, when the slidingbed 6 is thrusted forward by said thrusting unit the movement of saidsliding bed more than a predetermined distance under the influence ofacceleration created therein is restricted by said thrusting unitthrough said coupling arms 45, 45 and thus runaway of the hull block Acan be positively prevented. This eliminates the necessity for providinga special, large-scaled braking menas which has been provided in theconventional devices and is very effective in preventing runaway of thehull block even when the fixed rail plates 2, 2 have a gradient.

Although the present invention has been described and illustrated hereinin terms of a specific embodiment thereof, it should be understood thatthe invention is not restricted only to the embodiment shown but manychanges and modifications are possible to the detailed construction ofthe embodiment without deviat ing the technical scope of the invention.It should also be understood that the application of the thrustingdevice of the invention is not restricted only to the thrusting of shiphull blocks but to the thrusting of many other articles.

What is claimed is: l. A thrusting device comprising a plurality offixed rail plates for shifting an article to be shifted thereon, each ofsaid fixed rail plates being formed therein with substantially equallyspaced pin holes arranged substantially along the center line thereof,and at least one thrusting unit striding over a selected one of saidfixed rail plates and comprising running wheels provided at the bottomthereof for running along said fixed rail plate, one front block and onerear block arranged in opposed relation to each other, one thrustinghydraulic cylinder having one end connected to said front block and theother end to said rear block for thrusting said front block with saidother end bearing against said rear block, supporting meansv forsecuring both of said blocks alternately to said fixed rail platethrough said pin holes, two guide beams each having one end fixed tosaid front block and the central portion slidably supported by a bearingportion formed integrally with said rear block, and anti-stumbling meansconnected to said rear block rearwardly of said supporting means.

2. Apparatus for shifting a heavy object across a substantiallyhorizontal surface, by a plurality of successive increments of forwardmovement, comprising:

plate means extending on said surface and possessing at least onerow orregularly spaced upwardly open openings, said row longitudinallyextending in the direction of said forward movement;

carriage means for bearing the heavy object thereupon;

rolling support means provided between the plate means, flanking said atleast one row, and the carriage means;

a frame having rolling support means for rolling across said surface insaid direction;

a front block provided with a generally vertically directed, downwardlyextensible and upwardly retractable pin for insertion into andwithdrawal from successive ones of said upwardly open openings;

at rear block provided with a generally vertically directed, downwardlyextensible and upwardly retractable pin for insertion into andwithdrawal from successive ones of said upwardly open openings;

a hydraulic piston and cylinder arrangement extending generallylongitudinally, horizontally on said frame, the forward end thereofbeing connected to the front block and the rear end thereof being connected to the rear block;

hydraulic system means for extending and retracting said hydraulicpiston and cylinder arrangement;

a pair of longitudinally slidable guide members respectivelytransversally offset from the hydraulic I piston and cylinder and havingthe forward ends thereof fixed to the front block;

guide bearings on the frame and fixed to the rear block for supportingthe hydraulic piston and cylinder arrangement, front block, rear blockand guide members with respect to the frame, the guide members beingslidably received in the guide bearings for essentially longitudinalsliding;

connector means for securing the carriage means to the front block,

whereby the heavy object, supported on the carriage means may be shiftedacross the surface in said direction, by

extending the pin of the rear block down into an upwardly open openingwhile said hydraulic piston and cylinder arrangement is retracted andsaid connector means is connected and thepin of the front block isretracted, operating the hydraulic system to extend said hydraulicpiston and cylinder arrangement and thus thrust the front block,carriage and heavy object forwardly, extending the pin of the frontblock down into an upwardly open opening and retracting the pin of therear block from the opening into which it had been extended, operatingthe hydraulic system to retract said hydraulic piston and cylinderarrangement and thus recover the rear block toward the front block toprepare for the next increment of forward movement.

3. The apparatus of claim 2 further including surface engaging meansrigged by hydraulic piston and cylinder means to trail the rear blockand means for extending the last-mentioned piston and cylinder meanswhen the heavy object is being moved an increment forwardly to maintainthe apparatus in a generally level condition with respect to thesurface, countering a tendency of the rear block to be pushed downwardby the rear end of the first-mentioned piston and cylinder arrangement.

1. A thrusting device comprising a plurality of fixed rail plates forshifting an article to be shifted thereon, each of said fixed railplates being formed therein with substantially equally spaced pin holesarranged substantially along the center line thereof, and at least onethrusting unit striding over a selected one of said fixed rail platesand comprising running wheels provided at the bottom thereof for runningalong said fixed rail plate, one front block and one rear block arrangedin opposed relation to each other, one thrusting hydraulic cylinderhaving one end connected to said front block and the other end to saidrear block for thrusting said front block with said other end bearingagainst said rear block, supporting means for securing both of saidblocks alternately to said fixed rail plate through said pin holes, twoguide beams each having one end fixed to said front block and thecentral portion slidably supported by a bearing portion formedintegrally with said rear block, and anti-stumbling means connected tosaid rear block rearwardly of said supporting means.
 2. Apparatus forshifting a heavy object across a substantially horizontal surface, by aplurality of successive increments of forward movement, comprising:plate means extending on said surface and possessing at least one row orregularly spaced upwardly open openings, said row longitudinallyextending in the direction of said forward movement; carriage means forbearing the heavy object thereupon; rolling support means providedbetween the plate means, flanking said at least one row, and thecarriage means; a frame having rolling support means for rolling acrosssaid surface in said direction; a front block provided with a generallyvertically directed, downwardly extensible and upwardly retractable pinfor insertion into and withdrawal from successive ones of said upwardlyopen openings; a rear block provided with a generally verticallydirected, downwardly extensible and upwardly retractable pin forinsertion into and withdrawal from successive ones of said upwardly openopenings; a hydraulic piston and cylinder arrangement extendinggenerally longitudinally, horizontally on said frame, the forward endthereof being connected to the front block and the rear end thereofbeing connected to the rear block; hydraulic system means for extendingand retracting said hydraulic piston and cylinder arrangement; a pair oflongitudinally slidable guide members respectively transversally offsetfrom the hydraulic piston and cylinder and having the forward endsthereof fixed to the front block; guide bearings on the frame and fixedto the rear block for supporting the hydraulic piston and cylinderarrangement, front block, rear block and guide members with respect tothe frame, the guide members being slidably received in the guidebearings for essentially longitudinal sliding; connector means forsecuring the carriage means to the front block, whereby the heavyobject, supported on the carriage means may be shifted across thesurface in said direction, by extending the pin of the rear block downinto an upwardly open opening while said hydraulic piston and cylinderarrangement is retracted and said connector means is connected and thepin of the front block is retracted, operating the hydraulic system toextend said hydraulic piston and cylinder arrangement and thus thrustthe front block, carriage and heavy object forwardly, extending the pinof the front block down into an upwardly open opening and retracting thepin of the rear block from the opening into which it had been extended,operating the hydraulic system to retract said hydraulic piston andcylinder arrangement and thus recover the rear block toward the frontblock to prepare for the next increment of forward movement.
 3. Theapparatus of claim 2 further including surface engaging means rigged byhydraulic piston and cylinder means to trail the rear block and meansfor extending the last-mentioned piston and cylinder means when theheavy object is being moved an increment forwardly to maintain theapparatus in a generally level condition with respect to the surface,countering a tendency of the rear block to be pushed downward by therear end of the first-mentioned piston and cylinder arrangement.